Integrated circuit for sequence reporting and sequence generation

ABSTRACT

Disclosed are a sequence report method and a sequence report device for reducing a signaling amount for reporting a Zadoff-Chu sequence or a GCL sequence allocated for a cell. Indexes starting at 1 are correlated to different ZC sequences and are allocated for cells so that the indexes are continuous. When such ZC sequences are reported from BS to UE, a start index indicating the start of the continuous indexes is combined with the number of allocated sequences and they are reported as allocation sequence information by a report channel. The UE and the BS share the correlation between the ZC sequences and the indexes and the UE identifies a usable sequence number according to the correlation and the allocation sequence information reported from the BS.

TECHNICAL FIELD

The present invention relates to a sequence report method and sequencereport apparatus that report a Zadoff-Chu sequence or GCL (GeneralizedChirp-Like) sequence allocated to a cell.

BACKGROUND ART

In a mobile communication system typified by a cellular communicationsystem, or a wireless LAN (Local Area Network) system, a random accessfield is provided in a transmission field. This random access field isprovided in an uplink transmission field when a terminal station(hereinafter referred to as “UE”) initially makes a connection requestto a base station (hereinafter referred to as “BS”), or when a BS or thelike makes a new resource allocation request in a centralized managementsystem that allocates a UE transmission time and transmission band. Abase station may also be called an access point or Node B.

With a random access burst (hereinafter referred to as “RA burst”)transmitted in a random access field (hereinafter referred to as “RAslot”), unlike other scheduled channels, a reception error andretransmission occur due to a signature sequence collision (transmissionof an identical signature sequence using the same RA slot by a pluralityof UE's) or due to interference between signature sequences. When an RAburst collision or reception error occurs, the processing delay of RAburst uplink transmission timing synchronization acquisition and BSconnection request processing increases. Consequently, there is a demandfor a reduction in the signature sequence collision rate and animprovement in signature sequence detection performances.

In the mobile communication system described in Non-Patent Document 1,as an RA burst preamble (hereinafter referred to as “RA preamble”)sequence, an RA preamble sequence (or signature sequence) that uses aZadoff-Chu sequence (hereinafter referred to as “ZC sequence”) or GCLsequence (Non-Patent Document 2) having a low auto-correlationcharacteristic and inter-sequence cross-correlation characteristic isinvestigated. Also, the use of a ZC-ZCZ (Zadoff-Chu Zero CorrelationZone) sequence generated by performing a cyclic shift of a ZC sequenceis investigated.

With a ZC sequence and GCL sequence, an auto-correlation characteristicis optimum when its sequence number r and sequence length N satisfy arelatively prime (coprime) relationship. Also, with regard to across-correlation characteristic between two sequences, if the sequencenumbers are designated r₁ and r₂ respectively, the cross-correlationvalue is constant at √{square root over (N)} when the absolute value ofthe difference between r₁ and r₂ and sequence length N satisfy arelatively prime relationship. Therefore, when sequence length N is aprime number, a set of sequences for which an auto-correlationcharacteristic and cross-correlation characteristic are optimum isobtained for N−1 sequences—that is, all sequences with sequence numberr=1, 2, . . . , N−1.

Also, in the mobile communication system described in Non-PatentDocument 1, always allocating 64 ZC-ZCZ sequences to one cell isinvestigated. These 64 sequences include ZC sequences with differentsequence numbers and cyclic shift sequences—that is, ZC-ZCZsequences—generated from ZC sequences having the respective sequencenumbers.

The number of ZC-ZCZ sequences that can be generated from one ZCsequence depends on a cyclic shift amount between sequences. If thecyclic shift amount is designated Δ and the sequence length isdesignated N, the generated number of ZC-ZCZ sequences is expressed asfloor(N/Δ), where floor(x) represents the largest integer that does notexceed x. To consider a time (Δ_(time)) corresponding to cyclic shiftamount Δ, cyclic shift amount Δ is defined by a time range in which itis possible for an RA preamble transmitted from a UE to arrive.Specifically, cyclic shift amount Δ_(time) is set so as to be greaterthan the sum of the maximum round-trip expected value(T_(RoundTripDelay)) based on the propagation delay time between a BSand UE (T_(PropagationDelay)) and the maximum expected value of channelmultipath delay time (T_(DelaySpread))(Δ_(time)>2×T_(PropagationDelay)+T_(DelaySpread)).

Therefore, since the propagation delay time between a BS and UEincreases in proportion to the cell size (cell radius), the larger thecell size of a cell, the smaller is the number of ZC-ZCZ sequences thatcan be generated from one ZC sequence. Consequently, in order toallocate 64 preamble sequences to one cell, it is necessary to allocatemany ZC sequences with different sequence numbers to the cell.

A BS generates a broadcast channel with sequence numbers of sequencesused by a cell as allocation sequence information, and reports this toUE's present within the cell. Each UE generates an RA burst using a ZCsequence having a reported sequence number, and performs random access.A possible allocation sequence information report method is to reportsequence numbers of sequences used by a cell one at a time. This methodallows flexible sequence allocation since arbitrary sequence numbers areallocated to a cell.

-   Non-Patent Document 1: “3GPP TSG RAN; Physical Channels and    Modulation (Release 8),” TS36.211V1.0.0-   Non-Patent Document 2: “Generalized Chirp-Like Polyphase Sequences    with Optimum Correlation Properties,” Branislav M. Popovic, IEEE    Transaction on Information Theory, Vol. 38, No. 4, July 1992

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

However, with the above-described allocation sequence information reportmethod, in the case of a cell with a large cell radius it is necessaryto report a maximum of 64 ZC sequences, and the broadcast channelsignaling amount (number of bits) increases. Allocation sequenceinformation is information that is required by a OE before RA preambletransmission, and is therefore transmitted robustly (that is, using amodulation method providing low-transmission-data-rate, coding rate, andso forth) so as to enable it to be received correctly even by a UE in apoor reception environment. Consequently, as the signaling amountincreases, radio resources are consumed proportionally.

It is an object of the present invention to provide a sequence reportmethod and sequence report apparatus that reduce a signaling amount forreporting a Zadoff-Chu sequence or GCL sequence allocated to a cell.

Means for Solving the Problem

A sequence report apparatus of the present invention correlates indexeshaving consecutive numbers to a plurality of different code sequencesand allocates the indexes to cells so that the indexes are consecutive,and employs a configuration having a storage section that storescorrespondence relationships that correlate indexes having consecutivenumbers to a plurality of different code sequences, and a report sectionthat reports information combining an index indicating one of theallocated code sequences and information indicating the number ofallocated sequences as allocation sequence information based on thecorrespondence relationships.

A sequence report method of the present invention, based oncorrespondence relationships that correlate indexes having consecutivenumbers to a plurality of different code sequences, reports, asallocation sequence information, information which combines an indexindicating one of code sequences allocated to a cell such that theindexes are consecutive and information indicating the number ofallocated code sequences.

Advantageous Effects of Invention

The present invention enables a signaling amount for reporting aZadoff-Chu sequence or GCL sequence allocated to a cell to be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing a configuration of a wirelesscommunication system according to Embodiment 1 of the present invention;

FIG. 2 is a block diagram showing a configuration of a BS shown in FIG.1;

FIG. 3 is a block diagram showing a configuration of a UE according toEmbodiment 1 of the present invention;

FIG. 4 is a drawing showing an internal configuration of the preamblesequence detection section shown in FIG. 2;

FIG. 5 is a drawing showing correspondence relationships betweensequence numbers and indexes according to Embodiment 1 of the presentinvention;

FIG. 6 is a drawing showing a configuration of a broadcast channelaccording to Embodiment 1 of the present invention;

FIG. 7 is a flowchart showing the operation of the sequence allocationsection shown in FIG. 1;

FIG. 8 is a drawing showing a configuration of allocation sequenceinformation according to Embodiment 1 of the present invention;

FIG. 9 is a drawing showing correspondence relationships betweensequence numbers and indexes according to Embodiment 1 of the presentinvention;

FIG. 10 is a block diagram showing a distributed management type systemconfiguration;

FIG. 11 is a drawing showing correspondence relationships betweensequence numbers and indexes according to Embodiment 2 of the presentinvention;

FIG. 12 is a drawing showing a configuration of a broadcast channelaccording to Embodiment 2 of the present invention;

FIG. 13 is a drawing showing correspondence relationships betweennumbers of allocated sequences and report bits according to Embodiment 3of the present invention;

FIG. 14 is a drawing showing a configuration of a broadcast channelaccording to Embodiment 3 of the present invention;

FIG. 15 is a drawing showing correspondence relationships between anumber of cyclic shift sequences that can be generated from one sequenceand a required number of allocated sequences with respect to cell size(radius);

FIGS. 16A-C are drawings showing correspondence relationships betweensequence numbers and indexes according to Embodiment 4 of the presentinvention;

FIG. 17 is a drawing showing a configuration of a broadcast channelaccording to Embodiment 4 of the present invention;

FIG. 18 is a drawing showing correspondence relationships between indextypes and preamble sequence tables according to Embodiment 4 of thepresent invention;

FIG. 19 is a drawing showing correspondence relationships betweensequence numbers and indexes according to Embodiment 5 of the presentinvention;

FIG. 20 is a drawing showing a configuration of a broadcast channelaccording to Embodiment 5 of the present invention;

FIG. 21 is a drawing showing the relationship between a ZC sequencecorrelation value and cyclic shift amount Δ according to Embodiment 6 ofthe present invention;

FIG. 22 is a drawing showing correspondence relationships betweensequence numbers and indexes according to Embodiment 6 of the presentinvention;

FIG. 23 is a drawing showing correspondence relationships betweensequence numbers and indexes according to Embodiment 6 of the presentinvention; and

FIG. 24 is a drawing showing correspondence relationships betweensequence numbers and indexes according to Embodiment 6 of the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, embodiments of the present invention will be described in detailwith reference to the accompanying drawings.

Embodiment 1

First, a ZC sequence will be shown using equations. A ZC sequence ofsequence length N is represented by Equation (1) when N is an evennumber, and by Equation (2) when N is an odd number.

$\begin{matrix}\left( {{Equation}\mspace{14mu} 1} \right) & \; \\{{c_{r}(k)} = {\exp \left\{ {{- j}\frac{2\pi \; r}{N}\left( {\frac{k^{2}}{2} + {qk}} \right)} \right\}}} & \lbrack 1\rbrack \\\left( {{Equation}\mspace{14mu} 2} \right) & \; \\{{c_{r}(k)} = {\exp \left\{ {{- j}\frac{2\pi \; r}{N}\left( {\frac{k\left( {k + 1} \right)}{2} + {qk}} \right)} \right\}}} & \lbrack 2\rbrack\end{matrix}$

Here, k=0, 1, 2, . . . , N−1; q is an arbitrary integer; r is a sequencenumber (Sequence index); and r has a mutually prime relationship with N,and is a positive integer smaller than N.

Next, a GCL sequence will be shown using equations. A GCL sequence ofsequence length N is represented by Equation (3) when N is an evennumber, and by Equation (4) when N is an odd number.

$\begin{matrix}\left( {{Equation}{\mspace{11mu} \;}3} \right) & \; \\{{c_{r,m}(k)} = {\exp \left\{ {{- j}\frac{2\pi \; r}{N}\left( {\frac{k^{2}}{2} + {qk}} \right)} \right\} {b_{i}\left( {k\mspace{11mu} {mod}\mspace{11mu} m} \right)}}} & \lbrack 3\rbrack \\\left( {{Equation}\mspace{14mu} 4} \right) & \; \\{{c_{r,m}(k)} = {\exp \left\{ {{- j}\frac{2\pi \; r}{N}\left( {\frac{k\left( {k + 1} \right)}{2} + {qk}} \right)} \right\} {b_{i}\left( {k\mspace{11mu} {mod}\mspace{11mu} m} \right)}}} & \lbrack 4\rbrack\end{matrix}$

Here, k=0, 1, 2, N−1; q is an arbitrary integer; r has a mutually primerelationship with N, and is an integer smaller than N; b_(i)(k mod m) isan arbitrary complex number, and i=0, 1, . . . , m−1. Also, whenminimizing cross-correlation between GCL sequences, an amplitude 1arbitrary complex number is used for b_(i)(k mod m).

A GCL sequence is a sequence resulting from multiplying a ZC sequence byb_(i)(k mod m), and since receiving-side correlation computation issimilar to that for a ZC sequence, a ZC sequence will be taken as anexample in the following description. A case will be described below inwhich a ZC sequence for which sequence length N is an odd number and aprime number is used as an RA burst preamble sequence.

FIG. 1 is a block diagram showing a configuration of a wirelesscommunication system according to Embodiment 1 of the present invention.In this figure, radio resource management section 51 manages radioresources allocated to plurality of BS's (#1 through #M) 100-1 through100-M, and is equipped with sequence allocation section 52 and reportsection 53.

Sequence allocation section 52 allocates ZC sequence number r to a cellmanaged by a subordinate BS, and outputs allocated sequence number r toreport section 53. Report section 53 reports information indicatingsequence number r output from sequence allocation section 52 toplurality of BS's 100-1 through 100-M. Details of sequence allocationsection 52 and report section 53 will be given later herein.

Based on information indicating sequence number r reported from reportsection 53, BS's 100-1 through 100-M report allocation sequenceinformation to a UE within their own cell by means of a report methoddescribed later herein, and detects a preamble sequence transmitted fromthe UE. Since BS's 100-1 through 100-M all have identical functions,they will be treated collectively as BS 100 in the followingdescription.

FIG. 2 is a block diagram showing the configuration of BS 100 shown inFIG. 1. In this figure, broadcast channel processing section 101 isequipped with broadcast channel generation section 102, encoding section103, and modulation section 104. Based on information indicatingallocation sequence number r reported from report section 53 shown inFIG. 1, broadcast channel generation section 102 reads correspondinginformation from preamble sequence table storage section 113 andgenerates a broadcast channel that is a downlink control channelincluding the read information. The generated broadcast channel isoutput to encoding section 103.

Encoding section 103 encodes the broadcast channel output from broadcastchannel generation section 102, and modulation section 104 modulates theencoded broadcast channel using a modulation method such as BPSK orQPSK. The modulated broadcast channel is output to multiplexing section108.

DL data transmission processing section 105 is equipped with encodingsection 106 and modulation section 107, and performs DL transmissiondata transmission processing. Encoding section 106 encodes DLtransmission data, and modulation section 107 modulates encoded DLtransmission data using a modulation method such as BPSK or QPSK, andoutputs the modulated DL transmission data to multiplexing section 108.

Multiplexing section 108 performs time multiplexing, frequencymultiplexing, spatial multiplexing, or code multiplexing of thebroadcast channel output from modulation section 104 and the DLtransmission data output from modulation section 107, and outputs amultiplex signal to RF transmitting section 109.

RF transmitting section 109 executes predetermined radio transmissionprocessing such as D/Δ conversion, filtering, and up-conversion on themultiplex signal output from multiplexing section 108, and transmits asignal that has undergone radio transmission processing from antenna110.

RF receiving section 111 executes predetermined radio receptionprocessing such as down-conversion and A/D conversion on a signalreceived via antenna 110, and outputs a signal that has undergone radioreception processing to separation section 112.

Separation section 112 separates the signal output from RF receivingsection 111 into an RA slot and a UL data slot, and outputs theseparated RA slot to preamble sequence detection section 114, and theseparated UL data slot to demodulation section 116 of UL data receptionprocessing section 115.

Preamble sequence table storage section 113 stores a preamble sequencetable correlating preamble sequences that can be allocated by sequenceallocation section 52 shown in FIG. 1, corresponding sequence numbers,and indexes indicating these sequence numbers, reads a preamble sequencefrom the table based on information indicating allocation sequencenumber r reported from report section 53 shown in FIG. 1, and outputsthe relevant preamble sequence to preamble sequence detection section114.

Preamble sequence detection section 114 performs correlation processingand suchlike preamble waveform detection processing for an RA slotoutput from separation section 112 using a preamble sequence stored inpreamble sequence table storage section 113, and detects whether or nota preamble sequence has been transmitted from a UE. The detection result(RA burst detection information) is output to an upper layer not shownin the figure.

UL data reception processing section 115 is equipped with demodulationsection 116 and decoding section 117, and performs UL data receptionprocessing. Demodulation section 116 performs channel responsedistortion correction for UL data output from separation section 112,and performs signal point determination by means of a hard decision orsoft decision corresponding to the modulation method, and decodingsection 117 performs error correction processing for the result ofsignal point determination by demodulation section 116, and outputs ULreceived data.

FIG. 3 is a block diagram showing the configuration of UE 150 accordingto Embodiment 1 of the present invention. In this figure, RF receivingsection 152 receives a signal transmitted from BS 100 shown in FIG. 1via antenna 151, executes predetermined radio reception processing suchas down-conversion and A/D conversion on the received signal, andoutputs a signal that has undergone radio reception processing toseparation section 153.

Separation section 153 separates a broadcast channel and DL dataincluded in the signal received from RF receiving section 152, andoutputs the separated DL data to demodulation section 155 of DL datareception processing section 154, and the separated broadcast channel todemodulation section 158 of broadcast channel reception processingsection 157.

DL data reception processing section 154 is equipped with demodulationsection 155 and decoding section 156, and performs DL data receptionprocessing. Demodulation section 155 performs channel responsedistortion correction of DL data output from separation section 153, andperforms signal point determination by means of a hard decision or softdecision corresponding to the modulation method, and decoding section156 performs error correction processing for the result of signal pointdetermination by demodulation section 155, and outputs DL received data.

Broadcast channel reception processing section 157 is equipped withdemodulation section 158, decoding section 159, and broadcast channelprocessing section 160, and performs broadcast channel receptionprocessing. Demodulation section 158 performs channel responsedistortion correction of a broadcast channel output from separationsection 153, and performs signal point determination by means of a harddecision or soft decision corresponding to the modulation method, anddecoding section 159 performs error correction processing for the resultof broadcast channel signal point determination by demodulation section158. A broadcast channel that has undergone error correction processingis output to broadcast channel processing section 160. Broadcast channelprocessing section 160 outputs allocation sequence information includedin the broadcast channel output from decoding section 159 to preamblesequence table storage section 161, and outputs another broadcastchannel to an upper layer not shown in the figure.

Preamble sequence table storage section 161 stores a preamble sequencetable possessed by preamble sequence table storage section 113 of BS 100shown in FIG. 2—that is, a preamble sequence table correlating preamblesequences that can be allocated by sequence allocation section 52 shownin FIG. 1, corresponding sequence numbers, and indexes indicating thesesequence numbers. Then a preamble sequence corresponding to allocationsequence information output from broadcast channel processing section160 is output to RA burst generation section 162.

On acquiring an RA burst transmission directive from an upper layer notshown in the figure, RA burst generation section 162 selects one usablepreamble sequence from preamble sequence table storage section 161,generates an RA burst including the selected preamble sequence, andoutputs the generated RA burst to multiplexing section 166.

UL data transmission processing section 163 is equipped with encodingsection 164 and modulation section 165, and performs UL datatransmission processing. Encoding section 164 encodes UL transmissiondata, and modulation section 165 modulates encoded UL transmission datausing a modulation method such as BPSK or QPSK, and outputs themodulated UL transmission data to multiplexing section 166.

Multiplexing section 166 multiplexes the RA burst output from RA burstgeneration section 162 and the UL transmission data output frommodulation section 165, and outputs a multiplex signal to RFtransmitting section 167.

RF transmitting section 167 executes predetermined radio transmissionprocessing such as D/A conversion, filtering, and up-conversion on themultiplex signal output from multiplexing section 166, and transmits asignal that has undergone radio transmission processing from antenna151.

Next, preamble sequence detection section 114 shown in FIG. 2 will bedescribed. FIG. 4 is a drawing showing the internal configuration ofpreamble sequence detection section 114 shown in FIG. 2. A case is shownhere by way of example in which sequence length N=11, and a pair ofsequence number r=a and sequence number r=N−a ZC sequences are allocatedas a preamble sequence, where a represents an arbitrary sequence numberthat sequence number r can be.

In FIG. 4, if an input signal from delay device D is designatedr(k)=a_(k)+jb_(k), and each coefficient of a sequence number r=a ZCsequence is designated c_(r=a)*(k)=c_(k)+jd_(k), then for complexmultiplication section x, a computation result for sequence number r=aside correlation is a_(k)c_(k)−b_(k)d_(k)+j(b_(k)c_(k)+a_(k)d_(k)). Onthe other hand, each coefficient of a sequence number r=N−a ZC sequenceis c_(r=N−a)*(k)=(a_(r−a)*(k))*=c_(k)−jd_(k), and a computation resultfor sequence number r−N−a side correlation isa_(k)c_(k)+b_(k)d_(k)+j(b_(k)c_(k)−a_(k)d_(k)).

Therefore, as the result of multiplication computation performed toobtain a sequence number r=a side correlation value, a_(k)c_(k),b_(k)d_(k), b_(k)c_(k), and a_(k)d_(k) can be used for calculation of asequence number r=N−a side correlation value, the multiplicationcomputation amount can be reduced compared with reception processingwhen sequence number r=a and sequence number r=N−a are not allocated asa pair, and the circuit scale (number of multipliers) can be reduced.

Also, as can be seen from FIG. 4, one ZC sequence has a relationshipwith an even object sequence (sequence elements beingc_(r)(k)=c_(r)(N−1−k)), and therefore the number of multiplications(number of multipliers) can be further reduced by performingmultiplication processing whereby k and N−1−k elements are added priorto multiplication computation by a correlator.

Next, an actual method of reporting allocation sequence information willbe described.

FIG. 5 is a drawing showing a preamble sequence table according toEmbodiment 1 of the present invention. In FIG. 5, sequence number r=1 iscorrelated to index 1 and sequence number r=N−1to index 2, and sequencenumber r=2 is correlated to index 3 and sequence number r=N−2 to index4. The same kind of sequence number r correlation also applies fromindex 5 onward.

When sequence numbers are allocated to cells by sequence allocationsection 52 shown in FIG. 1, necessary number-of-sequences-K ZC sequencesare allocated to each cell in accordance with the table shown in FIG. 5so that indexes are consecutive. Information indicating sequence numberr of allocated sequences is reported to report section 53.

Report section 53 reports a ZC sequence allocated by sequence allocationsection 52 to BS 100 that is the allocation object. Broadcast channelgeneration section 102 of BS 100 generates a broadcast channel (BCH)including allocation sequence information reported from report section53.

FIG. 6 is a drawing showing the configuration of broadcast channel 300generated by broadcast channel generation section 102. Broadcast channelgeneration section 102 references preamble sequence table storagesection 113 storing the table shown in FIG. 5, and generates allocationsequence information 302 combining start index number 3021 indicating anindex correlated to the first index number of consecutively allocated ZCsequences and number of allocated sequences 3022 indicating theallocated number of ZC sequences. Allocation sequence information 302 isincluded in broadcast channel 300, and is reported to each UE.

Here, number of bits X of start index number 3021 is a number of bitsnecessary to report a ZC sequence number, and when the number ofsequences is N−1, X=ceiling(log₂(N−1)). Also, number of bits Y of numberof allocated sequences 3022 is a number of bits necessary to report themaximum number of allocations that can be made to one cell, M, whereY=ceiling(log₂(M)). Here, ceiling(x) represents x when x is an integer,and represents the smallest integer among integers larger than x when xis a non-integer value.

One index number and a number of allocated sequences decided in this wayare reported to UE 150 from BS 100 by means of a broadcast channel. Onthe UE 150 side, also, a table identical to the table shown in FIG. 5 isprovided in preamble sequence table storage section 161, and usablesequence numbers are identified using the reported single index numberand number of allocated sequences. UE 150 selects one sequence numberfrom among the identified usable sequence numbers, generates an RA burstincluding a preamble sequence, and transmits this in an RA slot.

FIG. 6 shows an example in which an index number at the start ofallocated sequences is reported, but an index number at the end, or at aspecific position decided beforehand among radio resource managementsection 51, BS 100, and UE 150, may also be used.

Next, the operation of sequence allocation section 52 shown in FIG. 1will be described using FIG. 7. In step (hereinafter abbreviated to“ST”) 401 in FIG. 7, counter a is initialized (a=1), and the number ofallocations to one cell is set to K.

In ST402, it is determined whether or not even one of K consecutivesequences from index number a to index number a+K−1 has been allocated.If none has been allocated (NO)—that is, if all K sequences areavailable for allocation—the processing flow proceeds to ST404 in orderto perform sequence allocation, whereas if even one of the K consecutivesequences has been allocated (YES), counter a is incremented (a=a+1) inST403, and the processing flow returns to ST402.

In ST404, sequences from index number a to index number a+K−1 areallocated, and sequence allocation processing is terminated. In ST401,ST402, and ST404, allocated sequences are shown as being searched for inascending sequence number order, but the search order (counter a order)is not limited to this.

FIG. 8 shows the configuration of a preamble sequence table andbroadcast channel allocation sequence information when ZC sequencelength N=839 and the maximum number of sequences that can be allocatedto one cell is 64.

Since sequence length N is prime number 839, the number of sequencesthat can be allocated is 838, and the number of indexes is also 838.Therefore, the number of bits necessary for an index number report is10. Also, since the number of allocations is 1 to 64 (maximum), thenumber of bits necessary for a number-of-allocated-sequences report issix. Therefore, the number of bits necessary for reporting an allocatedsequence number and number of sequences is always 16.

On the other hand, when arbitrary sequence numbers are allocated to onecell, assuming that 10 bits are needed for an index report for eachallocated sequence and the maximum number of allocated sequences is 64,a maximum of 640 bits (=10 bits×64 sequences) are necessary, andtherefore application of the report method of Embodiment 1 enables thenumber of signaling bits to be reduced from a maximum of 640 to 16,enabling the signaling amount to be reduced by a maximum of 97.5%.

Thus, according to Embodiment 1, the signaling overhead of allocationsequence information reported by a broadcast channel can be reduced.Also, since a fixed size is used irrespective of the number of allocatedsequences, the number of bits of allocation sequence information can bekept constant irrespective of the number of allocated sequences,enabling the size of a broadcast channel to be fixed, andtransmission/reception processing configurations to be simplified.

With regard to a method of reporting allocation sequence information toBS's 100-1 through 100-M from report section 53, also, the signalingamount can be reduced by reporting in the same way as with the method ofreporting from BS 100 to UE 150.

In this embodiment, a case has been described in which sequence length Nis a prime number (odd number), but sequence length N may also be anon-prime number (either odd or even). If sequence length N is anon-prime number, sequence number r having an optimum auto-correlationcharacteristic that is usable throughout the entire system must satisfythe condition of being mutually prime with respect to sequence length N.

As shown in FIG. 9, in a table stored in preamble sequence table storagesection 113, (a, N−a) pairs may be randomly arranged. The order of a ZCsequence pair (the a, N−a order) may be either a, N−a or N−a, a.

Also, in a table stored in preamble sequence table storage section 113,the ZC sequence number order (sequence number a order) may be arbitrary,may be a=1, 2, 3, 4, . . . , or may be a random allocation such as a=11,(N−1)/2, 1, . . . or the like. When such a preamble sequence table isused, as long as BS 100 and UE 150 share the same table, the signalingamount can be reduced in a similar way by reporting index numberscorrelated to sequence numbers shown in the table and the number ofallocated sequences.

In this embodiment, a preamble sequence used in random access has beendescribed as an example, but the present invention is not limited tothis, and can also be applied to a case in which a plurality of ZCsequences or GCL sequences are used by one BS as a known signal.Examples of such a known signal include a channel estimation referencesignal, a downlink synchronization pilot signal (Synchronizationchannel), or the like.

In this embodiment, a centralized management type system configurationhas been described in which there is one sequence allocation section 52for a plurality of BS's, as shown in FIG. 1, but a distributedmanagement type system configuration may also be used in which asequence allocation section is provided for each BS and informationexchange is performed among a plurality of BS's so that ZC sequenceswith mutually different sequence numbers r are allocated, as shown inFIG. 10.

Embodiment 2

The configurations of a radio resource management section, BS, and UEaccording to Embodiment 2 of the present invention are similar to theconfigurations shown in FIG. 1, FIG. 2, and FIG. 3 in Embodiment 1, andtherefore FIG. 1, FIG. 2, and FIG. 3 will be used in the followingdescription.

FIG. 11 is a drawing showing a preamble sequence table according toEmbodiment 2 of the present invention. In FIG. 11, sequence numbers r=1,N−1are correlated to index 1, and sequence numbers r=2, N−2 arecorrelated to index 2. The same kind of sequence number r correlationalso applies from index 3 onward.

When sequence numbers are allocated to cells by sequence allocationsection 52, necessary number-of-sequences-K ZC sequences are allocatedto each cell in accordance with the table shown in FIG. 11 so thatindexes are consecutive. Indexes of allocated sequences are reported toreport section 53.

Report section 53 reports an index of a sequence allocated by sequenceallocation section 52 to BS 100 that is the allocation object. Broadcastchannel generation section 102 of BS 100 generates allocation sequenceinformation based on an index reported from report section 53,Allocation sequence information is included in a broadcast channel.

FIG. 12 is a drawing showing the configuration of broadcast channel 310generated by broadcast channel generation section 102. Broadcast channelgeneration section 102 references preamble sequence table storagesection 113 storing the table shown in FIG. 11, and generates allocationsequence information 312 combining start index number 3121 and number ofallocated ZC sequence indexes 3122 indicating the number indexes ofallocated ZC sequences. Allocation sequence information 312 is includedin broadcast channel 310, and is reported to each UE.

In this embodiment, two sequence numbers are correlated to one index,and therefore the number of bits necessary to report the number ofindexes is X−1. Also, when the maximum number of indexes is M, thenumber of indexes for which allocation is performed is M/2, andtherefore the number of bits necessary to report the number of allocatedindexes is Y−1.

Here, number of bits X−1 of start index number 3121 and number of bitsY−1 of number of allocated indexes 3122 are defined in the same way asin Embodiment 1. That is to say, X is a number of bits necessary torepresent a ZC sequence number, and when the number of sequences is N−1,X−1=ceiling(log₂(N−1))−1. Also, number of bits Y is a number of bitsnecessary to report the maximum number of allocations that can be madeto one cell, M, where Y−1=ceiling(log₂(M))−1.

One index number and a number of allocated indexes decided in this wayare reported to UE 150 from BS 100 by means of a broadcast channel. Onthe UE 150 side, also, a table identical to the table shown in FIG. 11is provided in preamble sequence table storage section 161, and usablesequence numbers are identified using the reported single index numberand number of allocated sequences. UE 150 selects one sequence numberfrom among the identified usable sequence numbers, generates an RA burstincluding a preamble sequence, and transmits this in an RA slot.

FIG. 12 shows an example in which an index number at the start ofallocated sequences is reported, but an index number at the end, or at aspecific position decided beforehand among radio resource managementsection 51, BS 100, and UE 150, may also be used.

The effect of the above allocation sequence information report methodwhen ZC sequence length N=839, the number of sequences is 838, and themaximum number of sequences that can be allocated to one cell is 64, isdescribed below.

Since sequence length N is prime number 839, the number of sequencesthat can be allocated is 838, and the number of indexes is also 838.Since an index number is assigned to a pair of sequence numbers a, N−a,the number of bits necessary for an index number report is nine. Also,since the number of indexes is 1 to 32 (maximum), the number of bitsnecessary for a number-of-allocated-indexes report is five. Therefore,the number of bits necessary for reporting an allocated sequence numberand number of sequences is always 14.

On the other hand, when arbitrary sequence numbers are allocated to onecell, assuming that 10 bits are needed for an index report for eachallocated sequence and the maximum number of allocated sequences is 64,a maximum of 640 bits (=10 bits×64 sequences) are necessary, andtherefore application of the report method of Embodiment 2 enables thenumber of signaling bits to be reduced from a maximum of 640 to 14,enabling the signaling amount to be reduced by a maximum of 97.8%.

Thus, according to Embodiment 2, the signaling overhead of allocationsequence information reported by a broadcast channel can be furtherreduced while reducing the amount of computation of ZC sequencecorrelation processing.

In this embodiment, a case has been described in which one index iscorrelated to a pair of sequence numbers (a, N−a), but one index mayalso be correlated to a set of more than two sequence numbers, such as aset of four sequence numbers (a₁, N−a₁, a₂, N−a₂), a set of eightsequence numbers (a₁, N−a₁, a₂, N−a₂, a₃, N−a₃, a₄, N−a₄), and so forth.

As in Embodiment 1, in a table stored in preamble sequence table storagesection 113, (a, N−a) pairs may be randomly arranged. The order of a ZCsequence pair (the a, N−a order) may be either a, N−a or N−a, a. Also,one index may be correlated to a random set of ZC sequences, such as (1,3), (2, N−4), (a, N−b), rather than using an (a, N−a) pair.

Embodiment 3

The configurations of a radio resource management section, BS, and UEaccording to Embodiment 3 of the present invention are similar to theconfigurations shown in FIG. 1, FIG. 2, and FIG. 3 in Embodiment 1, andtherefore FIG. 1, FIG. 2, and FIG. 3 will be used in the followingdescription.

Also, a preamble sequence table according to Embodiment 3 of the presentinvention is identical to the preamble sequence table shown in FIG. 5 inEmbodiment 1, but differs from Embodiment 1 in that the number ofsequences allocated to a cell is limited.

FIG. 13 is a drawing showing correspondence relationships betweennumbers of allocated sequences and report bits according to Embodiment 3of the present invention. FIG. 13 shows a case in which the maximumnumber of allocated sequences is 64, and the number of sequences thatcan be allocated to a cell is limited to a power of two. The reason whythe number of allocated sequences can be limited will be explained laterherein.

When ZC sequence numbers are allocated to cells by sequence allocationsection 52, necessary number-of-sequences-K ZC sequences are allocatedto each cell in accordance with the table shown in FIG. 5 so thatindexes are consecutive (the same as in FIG. 8). Here, possible valuesof number of sequences K are limited to the values shown in FIG. 13.Indexes of allocated sequences are reported to report section 53.

FIG. 14 is a drawing showing the configuration of broadcast channel 320generated by broadcast channel generation section 102. Broadcast channelgeneration section 102 references preamble sequence table storagesection 113 storing the tables shown in FIG. 5 and FIG. 13, andgenerates allocation sequence information 322 combining start indexnumber 3021 and number of allocated sequences 3222 of allocated ZCsequences. Allocation sequence information 322 is included in broadcastchannel 320, and is reported to each UE.

Here, number of bits Z of number of allocated sequences 3222 is a numberof bits necessary for report bits, and when possible numbers ofsequences are of P kinds, Z=ceiling(log₂(P)). Also, in the case of thenumbers of allocated sequences (seven kinds) shown in FIG. 13, number ofbits Z is three.

One index number and a number of allocated sequences decided in this wayare reported to UE 150 from BS 100 by means of a broadcast channel. Onthe UE 150 side, also, tables identical to the tables shown in FIG. 5and FIG. 13 are provided in preamble sequence table storage section 161,and usable sequence numbers are identified using the reported singleindex number and number of allocated sequences. UE 150 selects onesequence number from among the identified usable sequence numbers,generates an RA burst including a preamble sequence, and transmits thisin an RA slot.

FIG. 14 shows an example in which an index number at the start ofallocated sequences is reported, but an index number at the end, or at aspecific position decided beforehand among radio resource managementsection 51, BS 100, and UE 150, may also be used.

The reason why it is possible to limit the number of allocated sequenceswill now be explained using FIG. 15.

FIG. 15 is a drawing showing the relationship between a number of cyclicshift sequences that can be generated from one ZC sequence and arequired number of allocated sequences with respect to the cell size(cell radius) in the case of an 800 μs RA preamble length. Here, arequired number of allocated sequences is a number of ZC sequences withdifferent sequence numbers.

As an example, in the mobile communication system described inNon-Patent Document 1, 64 random access preamble sequences are alwaysused for one cell. At this time, 64 sequences comprise one or aplurality of cyclic shift sequences generated from one ZC sequence andZC sequences with different sequence numbers. If it is possible foreight cyclic shift sequences to be generated from one ZC sequence, atotal of 64 sequences are obtained by allocating eight ZC sequences withdifferent sequence numbers and generating eight cyclic shift sequencesfrom each ZC sequence.

An equation for which q=0 for a ZC sequence (Equation (2)) when thesequence length is an odd number and that includes cyclic shift amount Δis shown in Equation (5).

$\begin{matrix}\left( {{Equation}\mspace{14mu} 5} \right) & \; \\{{c_{r,l}(k)} = {\exp \left\{ {{- j}\frac{2\pi \; r}{N}\left( \frac{{k\left( {k + {1\Delta}} \right)}\left( {k + {l\; \Delta} + 1} \right)}{2} \right)} \right\}}} & \lbrack 5\rbrack\end{matrix}$

where l represents a cyclic shift sequence number, l=0, 1, . . . , L−1,and L represents a number of cyclic shift sequences.

The number of cyclic shift sequence that can be generated from one ZCsequence is defined by cyclic shift amount Δ. When Δ is small, thenumber of cyclic shift sequences that can be generated from one sequenceincreases, and when Δ is large, the number of cyclic shift sequencesthat can be generated from one sequence decreases. Number of cyclicshift sequences L is obtained from the equation L=floor(N/Δ).

Furthermore, cyclic shift amount Δ must be set so as to be greater thanround-trip propagation delay (Round trip delay) between BS 100 and UE150, and is therefore proportional to the service radius supported by acell. Therefore, as shown in FIG. 15, the number of cyclic shiftsequence that can be generated from one sequence decreases, while therequired number of allocated sequences increases, in proportion to thecell size (cell radius).

With regard to the number of allocated sequences, the configuration inEmbodiment 1 allows an arbitrary number from 1 to maximum number ofallocations M to be allocated, but in the case of a large number ofallocated sequences (for example, 17 to 31, 33 to 63, or the like) acell has an extremely large cell radius, and such numbers are actuallyalmost never used. On the other hand, most cells have a cell radius offrom several hundred meters to 10 km or so, and for such cells therequired number of allocated sequences is small.

Therefore, by widening (exponentially increasing) the interval betweenpossible numbers of sequences as the cell radius increases, as shown inFIG. 15, it is possible to reduce the signaling amount while maintaininga certain degree of freedom of sequence allocation.

The effect of the above allocation sequence information report methodwhen ZC sequence length N=839, the number of sequences is 838, themaximum number of sequences that can be allocated to one cell is 64, andthe number of allocated sequences is limited as shown in FIG. 13, isdescribed below.

Since sequence length N is prime number 839, the number of sequencesthat can be allocated is 838, and the number of indexes is also 838. Thenumber of bits necessary for an index number report is 10, as inEmbodiment 1. Also, the number of bits necessary for anumber-of-allocated-indexes report is three. Therefore, the number ofbits necessary for reporting an allocated sequence number and number ofsequences is always 13.

When arbitrary sequence numbers are allocated to one cell, assuming that10 bits are needed for an index report for each allocated sequence andthe maximum number of allocated sequences is 64, a maximum of 640 reportbits (=10 bits×64 sequences) are necessary, and therefore application ofthe report method of Embodiment 3 enables the number of signaling bitsto be reduced from a maximum of 640 to 13, enabling the signaling amountto be reduced by a maximum of 98.0%.

Thus, according to Embodiment 3, the signaling overhead of allocationsequence information reported by a broadcast channel can be furtherreduced while reducing the amount of computation of ZC sequencecorrelation processing.

Embodiment 4

The configurations of a radio resource management section, BS, and UEaccording to Embodiment 4 of the present invention are similar to theconfigurations shown in FIG. 1, FIG. 2, and FIG. 3 in Embodiment 1, andtherefore FIG. 1, FIG. 2, and FIG. 3 will be used in the followingdescription.

FIGS. 16A-C are drawings showing preamble sequence tables according toEmbodiment 4 of the present invention. In FIGS. 16A-C, correspondencerelationships between indexes and sequence numbers are set for eachnumber of allocated sequences. For example, when numbers of allocatedsequences are designated K=1, 2, 4, 8, 16, 32, 64, seven preamblesequence tables are provided.

FIG. 16A shows a preamble sequence table for number of allocatedsequences 1. In FIG. 16A, one sequence number is allocated to one index.Specifically, sequence number r=1 is correlated to index 1 and sequencenumber r=N−1 to index 2, and sequence number r=2 is correlated to index3 and sequence number r=N−2 to index 4. The same kind of sequence numberr correlation also applies from index 5 onward,

FIG. 16B shows a preamble sequence table for number of allocatedsequences 2. In FIG. 16B, two sequence numbers are allocated to oneindex. Specifically, sequence numbers r=1 and r=N−1are correlated toindex 1, and sequence numbers r=2 and r=N−2 are correlated to index 2.The same kind of sequence number r correlation also applies from index 3onward.

FIG. 16C shows a preamble sequence table for number of allocatedsequences 4. In FIG. 16C, four sequence numbers are allocated to oneindex. Specifically, sequence numbers r=1, r=2, r=N−1, and r=N−2 arecorrelated to index 1, and sequence numbers r=3, r=4, r=N−3, and r=N−4are correlated to index 2. The same kind of sequence number rcorrelation also applies from index 3 onward. An index and sequencenumbers equivalent to the number of allocated sequences are alsocorrelated in a similar way for number of allocated sequences 8 onward.

When ZC sequence numbers are allocated to cells by sequence allocationsection 52, sequences are allocated to each cell in accordance withnumber of allocated sequences K and a preamble sequence tablecorresponding to the number of allocations (FIGS. 16A-C), and allocatedsequence indexes are reported to report section 53.

Report section 53 reports an index reported from sequence allocationsection 52 to BS 100 that is the allocation object. Broadcast channelgeneration section 102 of BS 100 generates a broadcast channel includingan index reported from report section 53.

FIG. 17 is a drawing showing the configuration of broadcast channel 330generated by broadcast channel generation section 102. Broadcast channelgeneration section 102 references preamble sequence table storagesection 113 storing the tables shown in FIGS. 16A-C, and generatesallocation sequence information 332 combining index type 3321corresponding to number of allocations K and allocated index number3322. Allocation sequence information 332 is included in broadcastchannel 330, and is reported to each UE.

Here, number of bits Z of index type 3321 increases from 1 bit to 2bits, 3 bits, 4 bits, . . . , as number of allocations K increases from1 to 2, 4, 8, . . . , as shown in FIG. 18. Also, as shown in FIG. 18,when the start bit of allocation sequence information is 1, thisindicates a number of allocations 1 preamble sequence table, andindicates that allocation sequence information bits after the initial 1bit are an index number. Also, when the start bits of allocationsequence information are 01, this indicates a number of allocations 2preamble sequence table, and indicates that allocation sequenceinformation bits after the initial 2 bits are an index number.Thereafter, in the same way, a position in which a “1” bit appears atthe start of allocation sequence information represents an index type,and indicates that subsequent allocation sequence information bits arean index number.

In FIG. 18, an example has been shown in which a position in which a “1”bit first appears represents an index type, but “0” and “1” bits may bereversed, and a position in which a “0” bit first appears may representan index type.

On the other hand, as number of allocations K increases from 1 to 2, 4,. . . , the number of bits of an index number decreases 1 bit at a time.For example, when numbers of ZC sequences are allocated in multiplefashion to preamble sequence tables as shown in FIGS. 16A-C, if thenumber of sequences is designated N, number of indexes N₁, N₂, N₄, . . ., N₆₄, of each table corresponding to K=1, 2, 4, 8, 16, 32, 64 becomeN₁=N, N₂=floor(N/2), N₄=floor(N/4), N₆₄=floor(N/64), respectively, andtherefore the number of bits necessary for an index number report, ifdesignated X bits when K=1, becomes X-1 bits, X-2 bits, X-3 bits, X-4bits, X-5 bits, X-6 bits, respectively for K=2, 4, 8, 16, 32, 64.

Therefore, the number of bits of allocation sequence information 332combining index type 3321 and index number 3322 can be made a constant(X+1 bits) irrespective of number of allocations K. An index type andone index number in a preamble sequence table corresponding to the indextype decided in this way are reported to UE 150 from BS 100 by means ofa broadcast channel. On the UE 150 side, also, tables identical to thetables shown in FIGS. 16A-C and FIG. 18 are provided in preamblesequence table storage section 161, and usable sequence numbers can beidentified using the reported index type and one index number in apreamble sequence table corresponding to the index type. UE 150 selectsone sequence number from among the identified usable sequence numbers,generates an RA burst including a preamble sequence, and transmits thisin an RA slot.

The effect of the above allocation sequence information report methodwhen ZC sequence length N=839, the number of sequences is 838, themaximum number of sequences that can be allocated to one cell is 64, andthe number of allocated sequences is limited as shown in FIGS. 16A-C, isdescribed below.

Since number of allocated sequences K is limited to 1, 2, 4, 8, 16, 32,64, the number of tables per number of allocated sequences is seven.Since the sequence length is prime number 839, the number of sequencesis 838, and the number of bits necessary for an index number of eachtable corresponding to number of allocated sequences K=1, 2, 4, 8, 16,32, 64 is 10 bits, 9 bits, 8 bits, 7 bits, 6 bits, and 5 bits,respectively. On the other hand, the number of bits necessary for anindex type (table type) report is 1 bit, 2 bits, 3 bits, 4 bits, 5 bits,and 6 bits for each table with number of allocated sequences K=1, 2, 4,8, 16, 32, 64. Therefore, the number of bits necessary for reporting anallocated sequence number and number of sequences is always 11.

When arbitrary sequence numbers are allocated to one cell, assuming that10 bits are needed for an index report for each allocated sequence andthe maximum number of allocated sequences is 64, a maximum of 640 reportbits (=10 bits×64 sequences) are necessary, and therefore application ofthe report method of Embodiment 4 enables the number of signaling bitsto be reduced from a maximum of 640 to 11, enabling the signaling amountto be reduced by a maximum of 98.3%.

Thus, according to Embodiment 4, the signaling overhead of allocationsequence information reported by a broadcast channel can be furtherreduced while reducing the amount of computation of ZC sequencecorrelation processing.

In FIGS. 16A-C, a configuration is shown by way of example in which anascending order of a is used for the ZC sequence number a and N−a orderof each preamble sequence table, but a descending order may be used, ora random order may be used.

Furthermore, the sequence number order may be different for eachpreamble sequence table.

Embodiment 5

The configurations of a radio resource management section, BS, and UEaccording to Embodiment 5 of the present invention are similar to theconfigurations shown in FIG. 1, FIG. 2, and FIG. 3 in Embodiment 1, andtherefore FIG. 1, FIG. 2, and FIG. 3 will be used in the followingdescription.

FIG. 19 is a drawing showing a preamble sequence table according toEmbodiment 5 of the present invention. In FIG. 19, one index number isallocated to each preset allocation sequence combination. For example,when the number of ZC sequences is N−1, one of sequence numbers Ithrough N−1 is allocated respectively to index numbers 1 through N−1, apair of sequence numbers is allocated to index numbers N through i, anda set of four sequence numbers is allocated to index numbers i+1 throughj. Preset combinations of allocated sequences are also allocated in asimilar way for index number i+j onward. As number of index numbers N₂necessary for a part in which a pair of sequences is correlated to oneindex number, N₂=i−N=floor(N/2). Similarly, as number of index numbersN_(x) necessary for a part in which a set of X sequences is correlatedto one index number, N_(x)=floor(N/X).

Sequence allocation section 52 allocates a sequence set corresponding toa number of allocations in accordance with the preamble sequence tableshown in FIG. 19. Report section 53 reports a ZC sequence allocated bysequence allocation section 52 to BS 100 that is the allocation object.Broadcast channel generation section 102 of BS 100 generates a broadcastchannel including allocation sequence information reported from reportsection 53.

FIG. 20 is a drawing showing the configuration of broadcast channel 340generated by broadcast channel generation section 102. Broadcast channelgeneration section 102 references preamble sequence table storagesection 113 storing the table shown in FIG. 19, generates broadcastchannel 340 including index number 3421 corresponding to a set ofallocation sequence numbers reported from report section 53, and reportsthis to each UE.

Thus, in Embodiment 5, there is a preamble sequence table that indicatescorrespondence relationships between allocation sequence numbers andindexes, and indexes comprise index numbers correlated to one sequencenumber and index numbers correlated to a plurality of sequence numberscombining sequence number r=a and sequence number r=N−a. BS 100 storesthe preamble sequence table shown in FIG. 19.

When the sequence length is N, number of indexes N₁ correlated to asingle sequence number is N−1, and for number of indexes N₂ correlatedto two sequence numbers, N₂=floor(N/2). Similarly, for number of indexesN_(x) correlated to X sequence numbers, N_(x)=floor(N/X). Thus, a parthaving more allocated sequences correlated to one index number in thepreamble sequence table shown in FIG. 19 has fewer index numbers.

BS 100 references the stored table shown in FIG. 19, and decides acorresponding index number from an allocation sequence and number ofsequences. The decided single index number is reported to UE 150 from BS100 by means of a broadcast channel. On the UE 150 side, also, a tableidentical to the table shown in FIG. 19 is provided in preamble sequencetable storage section 161, and usable sequence numbers are identifiedusing the reported single index number and number-of-allocationsinformation.

In the report method of Embodiment 5, only sequence number combinationsused by the system are set beforehand, and therefore, for example, thenumber of cells having a large cell size—that is, having a large numberof allocated sequences—is smaller than the number of cells having asmall cell size—that is, having a small number of allocatedsequences—making it possible to reduce the number of sequence numbersets.

On the other hand, for example, since many sequence number sets having asmall number of allocated sequences are obtained (N sets are obtainedfor number of allocated sequences 1), it is also possible to reduce thenumber of sequence number sets for a number of allocated sequences forwhich a large number of sequence number sets are obtained.

Therefore, since only an actually necessary number of sequence numbercombinations are reported, the number of bits used for an index numberreport can be utilized in a non-wasteful manner, and the signalingoverhead of allocation sequence information reported by a broadcastchannel can be reduced.

Thus, according to Embodiment 5, the signaling overhead of allocationsequence information reported by a broadcast channel can be reducedwhile reducing the amount of computation of ZC sequence correlationprocessing.

Embodiment 6

In Embodiment 1, a report method was shown whereby a start index numberand number of allocated sequences are reported in accordance with apreamble sequence table, but the arrangement of sequences in a table wasnot considered.

Here, when UE's moving at high speed are present and cyclic shiftsequences with different cyclic shift amounts are employed within thesame cell, high-speed-movement related Doppler spread and frequencyoffset are involved in a received signal, and therefore a highcorrelation value occurs in a detection range of separate cyclic shiftsequences generated from the same ZC sequence—that is, at a wrong timingposition. On the other hand, a correlation value in an expecteddetection range decreases.

When a high correlation value occurs in a detection range of differentcyclic shift sequences, the false detection probability for differentcyclic shift sequences increases. Also, when a correlation value in anexpected detection range decreases, the detection probability of atransmitted preamble becomes lower.

FIG. 21 is a drawing showing the relationship between a correlationvalue and cyclic shift amount Δ of a ZC sequence transmitted from a UEwhen moving at high speed. As shown in FIG. 21, with regard to acorrelation value for a preamble transmitted from a UE when moving athigh speed, a correlation value peak occurs at timing that is wrong ina + direction or − direction equivalent to timing x corresponding to asequence number of a ZC sequence described later herein with respect totiming of a correlation value detected when there is no Doppler spreador frequency offset transmitted from a stationary UE. Generally, withregard to the size of a correlation value peak, an erroneous correlationvalue peak increases while a correct-timing peak value decreases as thespeed of movement of a UE increases. Therefore, if a set cyclic shiftamount Δ value is greater than x (Δ>x), erroneous detection occurs inpeak detection processing by a base station, and it is thereforenecessary for cyclic shift amount Δ to be set to a value smaller than x(Δ<x).

In a conventional report method, it is possible to individually selectand report a sequence number and cyclic shift amount for which erroneousdetection does not occur so that a separate cyclic shift sequencedetection range and a correlation value range in which a wrong timing ofthat separate cyclic shift sequence occurs do not overlap in acorrelation value range in which a wrong timing occurs, but individualreporting cannot be performed in a report method of the presentinvention.

Thus, a preamble sequence table setting example will be shown thatfocuses on the fact that a difference between a position of acorrelation value at which a used sequence occurs at a wrong timing anda correct-timing position depends on a sequence number, and usablesequence numbers are limited by the cell radius since a range in which acorrelation value occurs depends on the cell radius.

The configurations of a radio resource management section, BS, and UEaccording to Embodiment 6 of the present invention are similar to theconfigurations shown in FIG. 1, FIG. 2, and FIG. 3 in Embodiment 1, andtherefore FIG. 1, FIG. 2, and FIG. 3 will be used in the followingdescription.

FIG. 22 is a drawing showing a preamble sequence table according toEmbodiment 6 of the present invention. In FIG. 22, index numbers areallocated one at a time to sequence numbers r in a case in whichsequence length N is 37 (a prime number). Sequence length N is notlimited to 37.

A preamble sequence table is used in which, when ZC sequences defined inthe time domain as in Equations (1) through (5) in the above embodimentsare used, indexes are allocated in a sequence number r order thatsatisfies following Equation (6) for u=1, 2, 3, . . . , N−1.

(Equation 6)

(r·u)mod N=N−1,u=1,2,3,. . . ,N−1 . . .   [6]

When sequence length N in FIG. 22 is 37, sequence number r=1 iscorrelated to index 1, and sequence number r=18 to index 2. A value of rthat satisfies Equation (6) is also correlated in a similar way to index3 onward. The sequence number r order may also be an order thatsatisfies Equation (6) for u=N−1, N−2, . . . , 3, 2, 1.

Sequence allocation section 52 performs sequence set allocationcorresponding to a number of allocations in accordance with the preamblesequence table shown in FIG. 22. Report section 53 reports a ZC sequenceallocated by sequence allocation section 52 to BS 100 that is theallocation object. Broadcast channel generation section 102 of BS 100generates a broadcast channel including allocation sequence informationreported from report section 53.

Broadcast channel generation section 102 references preamble sequencetable storage section 113 storing the table shown in FIG. 22, andgenerates allocation sequence information 302 combining start indexnumber 3021 and number of allocated sequences 3022 of allocated ZCsequences. Allocation sequence information is included in broadcastchannel 300, and is reported to each UE.

One index number and a number of allocations decided in this way arereported to UE 150 from BS 100 by means of a broadcast channel. On theUE 150 side, also, a table identical to the table shown in FIG. 22 isprovided in preamble sequence table storage section 161, and usablesequence numbers are identified using the reported single index numberand number-of-allocations information.

In the report method of Embodiment 6, BS 100 allocates sequences withconsecutive sequence numbers to the same cell based on a preamblesequence table set by means of Equation (6). If this table is used,relative differences x between a position of a correlation value thatoccurs at a wrong timing and a position of a correlation value thatoccurs at correct timing are arranged in the order +/−1, +/−2, +/−18,+/−18, +/−17, +/−1.

In base station 100, it is necessary for setting to be performed so thatcyclic shift amounts Δ for a correlation value that occurs at correcttiming and a correlation value that occurs at a wrong timing do notmutually overlap in order to prevent the occurrence of erroneousdetection of a preamble. That is to say, it is necessary for thecondition cyclic shift amount Δ<relative difference x to be satisfied.Therefore, as shown in FIG. 23, applicable cyclic shift amount Δ valuesare also 1, 2, . . . , 18, 18, 17, . . . , 1.

On the other hand, required cyclic shift amount Δ is set so as to begreater than the sum of the maximum round-trip propagation delay time(T_(PropagationDelay)) expected value between BS 100 and UE 150supported by the relevant cell and the maximum expected value of channelmultipath delay time (T_(DelaySpread)). That is to say, setting isperformed so that required cyclic shift amountΔ>2×T_(RoundTripDelay)+T_(DelaySpread). Therefore, sequence numbers thatcan be applied to this cell are limited to sequences for which relativedifference x satisfies the condition x>shift amountΔ>2×T_(RoundTripDelay)+T_(DelaySpread).

In the preamble sequence table shown in FIG. 23, applicable cyclic shiftamount Δ(<x) values are arranged in ascending order and descendingorder—that is, sequence numbers are arranged in an order proportional tothe cell radius—and therefore even if N sequences are allocatedconsecutively, it is easy to perform allocation so that a sequence thatcannot be utilized due to cell radius constraints is not included.

Also, since differences between a position of a correlation value thatoccurs at a wrong timing and a position of a correlation value thatoccurs at correct timing are allocated to index numbers in ascendingorder (index numbers 1 through floor(N/2)) and descending order (indexnumbers floor(N/2) through N−1), it is possible for sequence number rfor which a range in which a correlation value occurs is in a closerelationship to be allocated, it is possible for sequence allocation tobe performed such that the number of cyclic shift sequences that can begenerated from one ZC sequence is maximized, and sequence consumptioncan be reduced.

Thus, according to Embodiment 6, it is possible to report only usablesequence allocations in a non-wasteful manner even in a cell in which aUE moving at high speed is present, while reducing the signalingoverhead of allocation sequence information reported by a broadcastchannel.

A preamble sequence table may also employ an r order that satisfiesEquation (7) for u. FIG. 24 shows an example of a preamble sequencetable that satisfies Equation (7) when sequence length N=37. That is tosay, sequence number r=N−1 corresponding to u=1 is allocated to indexnumber 1, sequence number r=1 corresponding to u=N−1 is allocated toindex number 2, and sequence number r corresponding to u satisfyingEquation (7) is also allocated in a similar way for index number 3onward.

(Equation 7)

(r·u)mod N=N−1,u=1,N−1,2N−2,3,N−3 , . . . , floor(N/2),N−floor(N/2)  [7]

In this case, for a sequence number r=a and r=N−a pair an applicablecell radius, position of a correlation value argument at a wrong timing,and so forth, are identical, and therefore it is further possible toreport only usable sequence allocations in a non-wasteful manner even ina cell in which UE 150 moving at high speed is present. Also, inEquation (7), usable cyclic shift amount Δ is the same for a u=b andu=N−b order, and therefore either a u=b, u=N−b or a u=N−b, u=b order maybe used.

A configuration applying Equation (6) and Equation (7) to an a order forsequence numbers a and N−a described in above Embodiments 1 through 5may also be used.

Above Equation (6) may also be Equation (8) below.

(Equation 8)

(r·u)mod N=1,u=1,2,3, . . . ,N−1  [8]

In the above embodiments, descriptions have been given using ZCsequences, but the present invention is not limited to this, and GCLsequences may also be used.

Regarding the sign within exp of a ZC sequence and GCL sequence inEquations (1) through (5), −j may be used or +j may be used.

In the above embodiments, configurations have been shown in which anumber of allocated sequences or number of indexes is reported, but in asystem that makes combined use of cyclic shift sequences, if the numberof RA preambles used in a cell is known beforehand by a BS and UE, aconfiguration may be used in which a number of cyclic shift sequences isreported instead of reporting a number of allocated sequences or numberof indexes. This is because a number of allocated sequences or number ofindexes can be acquired by dividing the number of preambles used in acell by the number of cyclic shift sequences.

Also, in a system that makes combined use of cyclic shift sequences, ifthe number of RA preambles used in a cell is known beforehand by a BSand UE, a configuration may be used in which cyclic shift amount Δ isreported instead of reporting a number of allocated sequences or numberof indexes. This is because a number of allocated sequences or number ofindexes can be acquired from a number of cyclic shift sequences obtainedfrom sequence length N and cyclic shift amount Δ.

Furthermore, in a system that makes combined use of cyclic shiftsequences, if the number of RA preambles used in a cell is knownbeforehand by a BS and UE, a configuration may be used in which the cellsize (radius) is reported instead of reporting a number of allocatedsequences or number of indexes. This is because a number of allocatedsequences or number of indexes can be acquired by obtaining requiredcyclic shift amount Δ from the cell size (radius).

In the above embodiments, configurations have been shown in which apreamble sequence table is used for correspondence relationships betweensequence numbers and indexes, but a configuration may also be used inwhich a correspondence relationship between a sequence number and indexis obtain by means of an equation, such as sequence number=f(indexnumber).

In the above embodiments, cases have been described by way of example inwhich the present invention is configured as hardware, but it is alsopossible for the present invention to be implemented by software.

The function blocks used in the descriptions of the above embodimentsare typically implemented as LSI' s, which are integrated circuits.These may be implemented individually as single chips, or a single chipmay incorporate some or all of them. Here, the term LSI has been used,but the terms IC, system LSI, super LSI, and ultra LSI may also be usedaccording to differences in the degree of integration.

The method of implementing integrated circuitry is not limited to LSI,and implementation by means of dedicated circuitry or a general-purposeprocessor may also be used. An FPGA (Field Programmable Gate Array) forwhich programming is possible after LSI fabrication, or a reconfigurableprocessor allowing reconfiguration of circuit cell connections andsettings within an LSI, may also be used.

In the event of the introduction of an integrated circuit implementationtechnology whereby LSI is replaced by a different technology as anadvance in, or derivation from, semiconductor technology, integration ofthe function blocks may of course be performed using that technology.The application of biotechnology or the like is also a possibility.

The disclosure of Japanese Patent Application No.2007-071194, filed onMar. 19, 2007, including the specification, drawings and abstract, isincorporated herein by reference in its entirety.

INDUSTRIAL APPLICABILITY

A sequence report method and sequence report apparatus according to thepresent invention enable a signaling amount (number of bits) of abroadcast channel that reports different ZC sequences or GCL sequencesallocated to one cell from a base station to a terminal to be reduced,and are suitable for use in a mobile communication system or the like,for example.

1. A non-transitory computer-readable medium having contents which causecommunication circuitry to perform a method of selecting a preamblesequence, the method comprising: extracting allocated-sequenceinformation from a received signal, the allocated-sequence informationindicating an allocation of at least two consecutive sequences of anarrangement of a plurality of sequences, each of the plurality ofsequences having a difference between a position of a correlation valuethat occurs at a wrong timing and a position of a correlation value thatoccurs at a correct timing, the plurality of sequences being arranged inaccordance with the differences and the arrangement including: a firstsubset of the plurality of sequences arranged such that the differencesgenerally increase in the arrangement of the first subset; and a secondsubset of the plurality of sequences arranged such that the differencesgenerally decrease in the arrangement of the second subset; andselecting a preamble sequence based on the extracted allocated-sequenceinformation.
 2. The non-transitory computer-readable medium of claim 1wherein the differences for the first subset of the plurality ofsequences and the differences for the second subset of the plurality ofsequences are close to a specific value near a middle of the arrangementof the plurality of sequences.
 3. The non-transitory computer-readablemedium of claim 1 wherein the sequences having the differences betweenthe position of the correlation value that occurs at the wrong timingand the position of the correlation value that occurs at the correcttiming which are farthest away from the specific value are arranged atends of the arrangement of the plurality of sequences.
 4. Thenon-transitory computer-readable medium of claim 1 wherein theallocated-sequence information comprises an amount of a cyclic shift. 5.An integrated circuit including circuitry which, in operation, controlsa process, the process comprising: extracting allocated-sequenceinformation from a received signal, the allocated-sequence informationindicating an allocation of at least two consecutive sequences of anarrangement of a plurality of sequences, each of the plurality ofsequences having a difference between a position of a correlation valuethat occurs at a wrong timing and a position of a correlation value thatoccurs at a correct timing, the plurality of sequences being arranged inaccordance with the differences and the arrangement including: a firstsubset of the plurality of sequences arranged such that the differencesgenerally increase in the arrangement of the first subset; and a secondsubset of the plurality of sequences arranged such that the differencesgenerally decrease in the arrangement of the second subset; andselecting a preamble sequence based on the extracted allocated-sequenceinformation.
 6. The integrated circuit of claim 5, comprising: one ormore inputs coupled to the circuitry, wherein at least one of the one ormore inputs, in operation, receives the received signal.
 7. Theintegrated circuit of claim 5 wherein the differences for the firstsubset of the plurality of sequences and the differences for the secondsubset of the plurality of sequences are close to a specific value neara middle of the arrangement of the plurality of sequences.
 8. Theintegrated circuit of claim 7 wherein the sequences having thedifferences between the position of the correlation value that occurs atthe wrong timing and the position of the correlation value that occursat the correct timing which are farthest away from the specific valueare arranged at ends of the arrangement of the plurality of sequences.9. The integrated circuit of claim 5 wherein the allocated-sequenceinformation comprises an amount of a cyclic shift.
 10. The integratedcircuit of claim 6 wherein the at least one of the one or more inputs,in operation, couples to an antenna system.
 11. The integrated circuitof claim 5, comprising: one or more outputs coupled to the circuitry,wherein the process comprises generating one or more signals based onthe selected preamble sequence and at least one of the one or moreoutputs, in operation, outputs the one or more generated signals.